Triaryl phosphates



United States Patent ABSTRACT OF THE DISCLOSURE Organic phosphates ofthe formula R R4 lit (:7 O-PO H /t l L wherein R is alkyl of 1 to about8 carbon atoms; R R R and R are independently selected from the groupconsisting of hydrogen, alkyl of 1 to about 18 carbon atoms, andchlorine; n is from 0 to 2; and t is from 1 to 3. These compounds areespecially useful as plasticizers.

This invention relates to novel organic phosphates. More particularly,it relates to triaryl phosphates, such as those in which at least onearyl radical contains at least one benzyl or a-alkylbenzyl substituent.

Heretofore, various organic phosphorus compounds have been employed asplasticizers for various synthetic organic compositions of the typeexemplified by chloroprene, polyisobutylene, styrene, polyvinyl chlorideand the like. These conventional plasticizers normally tend to migratefrom the polymer with the passage of time, thus causing eventualembrittlement of the polymers. In addition, conventional plasticizerstend to be ineifective at temperatures much below room temperature.

It is an object of this invention to provide novel organic phosphateswhich possess improved plasticizing properties. Other-objects of theinvention will be apparent from the following detailed description.

In accordance with the practice of the invention, it has been discoveredthat the hereinbefore referred to object can be accomplished by use ofthe novel compounds of the invention. These may be prepared by reactingphosphorus oxyhalide with 1 to 3 molar proportions of a substitutedphenol carrying one or more substituents selected from the groupconsisting of alkyl, benzyl, a-alkylbenzyl and halogen, molarproportions being based on weight of phosphorus oxyhalide employed,adding to the reaction mixture sufiicient molar proportions of a hydroxycompound selected from the group consisting of phenol, alkyl-substitutedphenol and halo-substituted phenol, so that the molar proportions ofsubstituted phenol to phosphorus oxyhalide and of hydroxy compound tophosphorus oxyhalide add up to at least 3, thereafter separating thedesired phosphate from the reaction mixture. The term hydroxy compoundis used herein and in the appended claims to describe a group of thephenolic reactants employed in the process of the invention, namelyphenol, alkyl-substituted phenol and halo-substituted phenol.

3,428,714 Patented Feb. 18, 1969 ICC The novel organic phosphates of theinvention are characterized by the structural formula:

i i lilfi.

wherein R is selected from the group consisting of hydrogen and alkyl of1 to 8 carbon atoms, preferably of l to 4 carbon atoms, R R R and R areindependently selected from the group consisting of hydrogen, alkyl of lto 18 carbon atoms, preferably of 1 to 12 carbon atoms, most preferablyof l to 9 carbon atoms and halogen, of which chlorine is most preferred,n is from 0 to 2, and t is from 1 to 3. R R R and R may be the same ordifferent.

Illustrative examples of the novel organic phosphates which can beprepared by the process of this invention are the following:

Tris(4-a-methylbenzylphenyl) phosphate Tris(Z-a-methylbenzylphcnyl)phosphate Tris[2,4-di(u-methylbenzyl) phenyl] phosphateTris[2,6-di(a-methylbenzy1) phenyl] phosphateTris[2,4,6-tri(a-methylbenzyl) phenyl] phosphate Phenylbis(4-a-methylbenzylphenyl) phosphate Phenyl bis(2-a-methylbenzylphenyl)phosphate Tolyl bis (4-a-methylbenzylphenyl) phosphate Xylylbis(2-u-methylbenzylphenyl) phosphate Phenyl bis[2,4-di(umethylbenzyl)phenyl] phosphate Tolylbis[2,6-di(a-methylbenzy1) phenyl] phosphatePhenyl bis[2,4,6-tri(a-methylbenzyl) phenyl] phosphate Tolylbis[2,4,6-tri(a-methylbenzyl) phenyl] phosphate Phenylbis(2-a-methylbenzyl-4-chlor0phenyl) phosphate Phenylbis(2-a-methylbenzyl-4-cresyl) phosphate Nonylphenylbis(4-a-methylbenzylphenyl) phosphate Nonylphenylbis[2,4-di(a-methylbenzyl) phenyl] phosphate Nonylphenylbis[2,4,6-tri(a-methylbenzyl) phenyl] phosphate Diphenyl4-u-methylbenzylphenyl phosphate Ditolyl 2-a-methylbenzylphenylphosphate Dixylyl 2,4-di(a-methylbenzyl) phenyl phosphate, and

the like.

As the substituted phenols there may be employed compounds of thestructural formula:

wherein R R R and t are as previously described. Typical illustrativeexamples of the compounds characterized by the above formula are thefollowing:

Benzyl phenol 4-a-methylbenzyl phenol 2-a-methylbenzyl phenol2,4-di(a-methylbenzyl) phenol 2,4,6-tri(a-methylbenzyl) phenol2-a-methylbenzyl-4-chlorophenol 2-a-methylbenzyl-4-methyl phenol2-a-methylbenzyl-4-nonyl phenol, and the like.

3 As the hydroxy compounds there may be employed those of the structuralformula:

wherein R and R are as previously described. Illustrative of thecompounds characterized by the above formula are the following: phenol,cresol, xylenol, hexyl phenol, nonyl phenol, decyl phenol, chlorophenol,and the like.

As the phosphorus oxyhalide reactant of the present invention there maybe used compounds such as phosphorus oxybromide, phosphorus oxychlorideand phosphorus oxyfluoride. Of these, phosphorus oxychloride is mostpreferred.

In conducting the reaction, the phosphorus oxyhalide is charged to areaction vessel initially and the other reactants, namely, thesubstituted phenol and hydroxy compound, are added progressively duringthe course of the reaction. Usually, the reactants are introduced indesired molar proportions based upon the weight of phosphorus oxyhalideemployed. In practice, a stoichiometric quantity of 1 to 3 molarproportions of substituted phenol is added to the phosphorusoxychloride, the number of molar proportions employed depends on theextent of substitution desired. Thereafter, quantities of up to molarproportions of hydroxy compound may be added to complete thesubstitution. Generally, however, up to 2 molar proportions areemployed. It is to be noted that preferably the substituted phenol andhydroxy compound are employed in molar proportions to phosphorusoxyhalide which add up to 3, but it is within the scope of the inventionto employ excess hydroxy compound. When such an excess is employed itmay be removed by any suitable method, such as distillation or the like.It is also evident that when 3 or more molar proportions of substitutedphenol are employed, the hydroxy compound will not be added to thereaction mixture. Accordingly, when a tris a-alkylbenzylphenyl phosphateis desired, the a-alkylbenzylphenyl is reacted in substantially 3 molarproportions based on phosphorus oxychloride employed, and the additionof hydroxy compound is omitted.

It is also within the scope of the invention first to prepare andseparate the phosphorohalodate reaction product produced by the reactionof phosphorus oxyhalide and substituted phenol, and thereafter reactsaid product with the hydroxy compound.

Reaction temperatures of from about 20 degrees centigrade to 300 degreescentigrade or more may be employed, the preferred temperatures usuallybeing from about 20 to 250 degrees centigrade. Conveniently, thehydrochloride by-product formed during the reaction may be eliminated atthe temperatures hereinbefore mentioned. Reaction times of from aslittle as about 3 to about 20 hours are in most cases sufiicient forcompletion of the reaction. If desired, a metallic chloride, such asmagnesium chloride, aluminum chloride, zinc chloride, and mixturesthereof, may be employed to increase the rate of reaction. When this isdone, the metallic chloride may be used in percentages ranging from 0.1to 5.0 percent, based on the weight of phosphorus oxyhalide employed.Further, the rate of reaction may also be increased by employingelevated reaction temperatures, super-atmospheric pressures orcombinations of both. Generally, temperatures ranging from 200 to 300degrees centigrade and pressures ranging from over 1 atmosphere to 5atmospheres are sufiicient to produce the desired increase in the rateof reaction.

When the reaction is completed, the desired product can be recovered byconventional techniques such as distillation, extraction,crystallization or the like. However, due to the high yields obtainablein many cases, especially when, as previously described, stoichiometricproportions of hydroxy compound and substituted phenol to phosphorusoxyhalide employed in the reaction add up to 3, separation of thedesired phosphate from the reaction mixture is not always required forutility of the product and in such cases may be omitted.

The compounds which are provided in accordance with this invention findparticular utility as new and useful plasticizers for various syntheticcompositions, for example, polyvinyl chloride, synthetic rubber, and thelike.

The following examples are presented to illustrate the novel compoundsof this invention and their preparation. It is to be understood that theexamples are not to be construed as limiting the invention, except asdefined in the appended claims. All temperatures are in degreescentigrade and all parts are by weight, unless otherwise mentioned.

EXAMPLE 1 Preparation of diphenyl a-methylbenzylphenyl phosphate Areaction vessel was charged with 766 parts of phosphorus oxychloride andto this were added 198 parts of 2-a-methylbenzylphenol with stirring.The reactor temperature was raised to and maintained at degreescentigrade so as to refiux the phosphorus oxychloride. Then 6 parts ofanhydrous magnesium chloride were added to the mixture, and the reactionwas continuously maintained at reflux until 36.5 parts of hydrogenchloride were collected. The excess phosphorus oxychloride was thenstripped and the product was distilled at a vapor temperature of 136degrees centigrade at 0.02 millimeter of absolute pressure. Thephosphorodichloridate obtained contained 22.9 percent of chlorine and9.82 percent of phosphorus. The calculated percentages of these elementsfor a-methylbenzylphenyl phosphorodichloridate are 22.55 percentchlorine and 9.84 percent of phosphorus. Thereafter, 151 parts of thea-methylbenzylphenyl phosphorodichloridate were added to a flaskcontaining 149 parts of hot phenol. Upon adding 0.1 part of magnesiumchloride hydrogen chloride evolution began. The reaction mixture wasmaintained at -145 degrees centigrade until 73 parts of hydrogenchloride were collected. The excess phenol was stripped off and theproduct was isolated as a residue. The product was found to contain 7.22percent of phosphorus. The calculated percentage of this element in C HO P is 7.2 percent. Infrared analysis of diphenyl a-methylbenzylphenylphosphate was consistent for points of structure such as aryl oxygenphosphorus bond, methyl to carbon bond, and P=O bond.

EXAMPLE 2 Preparation of phenyl bis[2,4,6-tri(u-methylbenzyl) phenyl]phosphate A reaction vessel equipped with a mechanical stirrer, heatingmantle, addition funnel, thermometer, vigreaux column, K-head,condenser, receiver and hydrogen chloride trap, was charged with 212.5parts of phosphorus oxychloride, and 4 parts of anhydrous magnesiumc-hloride. The reactor was heated to 94 degrees centigrade and theaddition of 1174 parts of 2,4,6-tri(u-methylbenzyl) phenol was started.As the addition progressed, the temperature was raised to 200-250degrees centigrade and maintained there for 21 hours. The reaction wasthen cooled and 465 parts of phenol were added, followed by heating at147-192 degrees centigrade for 14 hours. The excess phenol was strippedoff under water aspirator vacuum. The residual compound was found tocontain 3.13 percent of phosphorus. The calculated percentage ofphosphorus in C H O P is 3.3 percent. An infrared scan of phenylbis[2,4,6-tri(a-methylbenzyl) phenyl] phosphate was consistent forpoints of structure such as aryl oxygen phosphorous bond, methyl tocarbon bond, and =P=O bond.

On substitution of equimolar quantities of the compounds2,4-di(a-methylbenzyl) phenol, 2-a-methylbenzyl phenol, benzyl phenol,2-ot-methylbenzyl-4-methyl phenol, Z-a-methylbenzyl-4-chlorophenol or2-a-methylbenZy1-4- nonyl phenol, for the 2,4,6-tri(u-methylbenzyl)phenol, the corresponding phosphates are obtained.

EXAMPLE 3 Preparation of diphenyl 2,4,6-tri(or-methylbenzyl) phenylphosphate To the apparatus of Example 2 were added 1278 parts ofphosphorus oxychloride and 4 parts of anhydrous magnesium chloride. Themixture was brought to reflux, 626 parts of 2,4,6-tri(or-methylbenzyl)phenol added, and reflux maintained for 18 hours. Excess phosphorusoxychloride was then stripped off to a pot temperature of 180 degreescentigrade. The reaction mix was cooled and 670 parts of phenol wereadded, followed by heating at 100-145 degrees centigrade for 9 hoursuntil the hydrogen chloride evolution ceased. Excess phenol was stripped01f under water aspirator vacuum. The residual compound was found tocontain 4.91 percent of phosphorus. The calculated percentage ofphosphorus in C H O P is 4.86 percent. The infrared scan made ofdiphenyl 2,4,6-tri(cx methylbenzyl) phenyl phosphate was consistent forpoints of structure such as aryl oxygen phosphorus bond, methyl tocarbon bond, and P==O bond.

When equimolar quantities of 4-a-methylbenzyl phenol, 2-a-methylbenzylphenol, 2-u-methylbenzyl-4-chlorophenol or Z-a-methylbenzyl-4-methyl areused to replace the 2,4,6-tri(or-methylbenzyl) phenol, the correspondingphosphates are obtained. In the like manner, when phenol is replaced bycresol, xylenol or nonyl phenol, the corresponding compounds areobtained.

EXAMPLE 4 Preparation of tris(a-methyl-benzylphenyl) phosphate To theapparatus of Example 2 were added 1180 parts of a-methylbenzyl phenoland 178 parts of phosphorus oxychloride. The reactor was heated to 140degrees centigrade, 1 part of anhydrous magnesium chloride was added andthe temperature was maintained at 125-170 degrees centigrade and 225.7parts of a-methylbenzyl phenol was then stripped under high vacuum. Theresidual com-/ pound was found to contain 4.94 percent of phosphorus.The calculated percentage of the element in C H O P is 4.86 percentphosphorus. An infrared scan made was consistent with points ofstructure for trifle-methylbenzylphenyl) phosphate. Such points werearyl oxygen phosphorus bond, methyl to carbon bond, and P=O 'bond.

Upon replacement of the u-methylbenzyl phenol by equimolar quantities of2,4-di(a-methylbenzyl) phenol, 2,4,6 tri(m methylbenzyl) phenol,2-oc-II'l6thYlb6l1ZYl- 4-chlorophenol or 2-a-methylbenzyl-4-methylphenol, the corresponding phosphates are obtained.

EXAMPLE Di (nonylphenyl) u-methylbenzylphenyl phosphate To the apparatusof Example 2 were added 153.5 parts of phosphorus oxychloride and 1 partof anhydrous magnesium chloride. The mixture was heated to 60 degreescentigrade and 225.7 parts of a-methylbenzyl phenolwere added. Thetemperature was maintained there at 60 degrees centigrade for 1 hour andthen raised to reflux for 10 hours. After cooling the reactor to 60degrees centigrade, 444.2 parts of nonylphenol were added. The mixturewas heated for 1 hour at 60 degrees centigrade and 2 hours at 180degrees centigrade. Unreacted nonylphenol was then stripped off undervacuum. The desired product, namely, dinonylphenyl-a-methyl-benzylphenylphosphate was found to conain 4.13 percent of phosphorus. The calculatedpercentage of this element in C H O P is 4.35 percent. The novel producthas the formula:

EXAMPLE 6 Preparation of tris(a-methylbenzylphenyl) phosphate To theapparatus of Example 2 are added 1180 parts of u-methyl'benzyl phenoland 178 parts of phosphorus oxychloride. The reactor is gradually heatedto and maintained between 200 degrees centigrade and 250 degreescentigrade, at about 2 atmospheres of pressure, for about 12 hours.Excess a-methylbenzyl phenol is then stripped under high vacuum. Aninfrared scan of the residual product is made and is found to beconsistent with points of structure for tris(u-methylbenzylphenyl)phosphate. When the reaction is conducted at atmospheric pressurereaction times may range from about 12 hours to 20 hours.

What is claimed is:

1. An organic phosphate of the formula wherein R is alkyl of 1 to about8 carbon atoms; R R R and R are independently selected from the groupconsisting of hydrogen, alkyl of 1 to about 18 carbon atoms, andchlorine; n is from 0 to 2; and t is from 1 to 3. 2. An organicphosphate in accordance with claim 1 wherein n is 0.

3. A mixed organic phosphate in accordance with claim 1 wherein n is l.

4. Tris(4-ot-methylbenzylphenyl) phosphate. 5.Tris(2-a-methylbenzylphenyl) phosphate. 6. Tris[2,4-di(at-methylbenzyl)phenyl] phosphate. 7. Tris[2,4,6-tri(rat-methylbenzyl) phenyl]phosphate. 8. Phenyl bis(4-or-methylbenzylphenyl) phosphate. 9.Nonylphenyl bis(4-ot-methylbenzylphenyl) phosphate.

10. Phenyl bis[2,4-di(u-methylbenzyl) phenyl] phosphate.

11. Phenyl bis [2,4,6-tri(oc-methylbenzyl) phenyl] phosphate.

hlZ. Di(nonylphenyl) 4 0c -methylbenzylphenyl phosp ate.

h13. Di(nonylphenyl) Z-a-methylbenzylphenyl phosp ate.

h14. Diphenyl 2,4-di(m-methylbenzyl) phenyl phosp ate.

15. Diphenyl 2,4,6-tri(a-methylbenzyl) phenyl phosphate.

References Cited UNITED STATES PATENTS 2,225,285 12/ 1940 Moyle 260-966CHARLES B. PARKER, Primary Examiner.

A. H. SU'I'IO, Assistant Examiner.

US. Cl. X.R.

P0405) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3, +28, 71 Dated February 18, 1969 Inventofls) It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 5, line '42, should be corrected to read as follows:---centigrade for 12 hours. Excess g -methyl benzyl phenol Column5, l ine 72, the word after "to" should be corrected to read as---contain---.

SIGNED AND SEALED FEB 2 4 1970 (SEA Meat:

sawm Imus 1:. sum, .m. A some" Gamissioner of Patents

